[Measurement of DNA damage in forestomach squamous epithelium by alkaline elution assay]

The alkaline elution assay were applied for assessing DNA damage of forestomach squamous epithelium in the male F344 rat. The animals were starved for 18 hr and then given a single oral dose of the sample in saline or corn oil. After 3 hr the stomach was removed, opened along the greater curvature and washed with cold 0.024M EDTA-0.075M NaCl (pH 7.5). The mucosa of the forestomach was scraped off gently with the edge of a cover glass, and the stratified squamous epithelium was collected by scraping off firmly with the edge of a cover glass. Since the collected epithelium cells adhere to the pipettes, these cells were transferred onto a polycarbonate filter by using a micro spatula. The dose-dependent DNA damages (5 approximately 150 mg/kg) were observed after administration of 1-methyl-3-nitro-1-nitrosoguanidine (MNNG), a forestomach carcinogen.